Penetration components

Abstract

A method is provided for producing an article containing heat-treated tungsten carbide particles in a matrix of a bonding alloy. This method includes liquid metal infiltration. The tungsten carbide particles are preferably ellipsoidal, and the bonding alloy preferably contains copper. The tungsten carbide particles are preferably heat-treated before or during the liquid metal infiltration process. Articles prepared by this method are also provided.

Description

[Technical Field]

[0001] The present invention relates to a component manufactured by impregnating a metal alloy through a tungsten carbide powder bed to form a metal matrix composite (MMC). [Background technology]

[0002] In applications and industries requiring high wear resistance and / or high strength, several known methods exist for manufacturing components. These methods include sintering, substrate cladding, and liquid metal impregnation.

[0003] Sintering: Sintered WC components or cemented carbide WC components, most typically blends of WC with Co or Ni, are used in a variety of applications and industries where wear resistance and / or high strength are required. They are formed through a multi-stage process that includes one or more of the following: 1. Powder preparation 2. Blending 3. Agglomeration 4. Compression and solidification 5. Pre-sintering 6. Molding 7. Sintering 8. Hot isostatic pressurization 9. Finishing

[0004] The preparation of hard-phase tungsten monocarbide (WC) involves grinding, screening, and washing. Similar methods are used for soft-phase materials such as cobalt and nickel (1). Blending of the two materials (2) is achieved by mixing and, after a period of time, by a temporary binder such as wax. The material is agglomerated into small balls or into a press-ready (RTP) powder via a spray-drying tower (3). The RTP is often loaded into a mold in a uniaxial press. Loading of the material is often performed by a robot. After pressing, the raw components are extruded from the press (6). Dewaxing and sintering (7) are followed by high-pressure sintering (8) to form sintered parts. Finally, for high volume reduction, the parts are machined, tumbled, and finished overall (9).

[0005] Typically, once the material properties of the sintered composite are determined, the grain size of the monotungsten carbide is used. Monotungsten carbide has resistance to localized indentation at approximately 1800–2000 HV and deforms plastically at room temperature. The typical grain size range is 0.0001–0.010 mm, most typically 0.001–0.004 mm. The strength and ductility of the composite are modified by the grain size of the monotungsten carbide and the proportion of the soft phase. The soft phase can range from 5%–35% by weight, most typically 6%–10% by weight. The overall wear resistance of the composite material is limited by the hardness of the hard phase.

[0006] Substrate cladding: There are several methods of kinetic and thermal processes for forming a wear-resistant surface on a substrate. These methods include, but are not limited to, high-velocity oxygen-fuel (HVOF), plasma-transferred arc (PTA), thermal spray (TS), metal inert gas (MIS), and physical vapor deposition (PVD). The complexity of a typical manufacturing method can be understood from the following example: During drilling, a rotary, maneuverable tool is used to drill to the target location. Maneuverability is enabled by the mechanical engagement of retractable pads on the side of the tool. A typical manufacturing route includes the following: 1. Machining of stainless steel substrates 2. Placement of the diamond monolith within the recess 3. Application of cladding around recesses and diamond monoliths 4. Grinding of the hardened weld 5. Formation of bushings and pivot points by inserting carbide inserts into the holes.

[0007] Machining of steel into a complex geometric shape including recesses and holes for the pad to rotate (1). Mounting a diamond or carbide monolith into the recess (2). Applying a cladding layer on and around the monolith (3). Grinding to the precise profile is then performed by removing excess cladding and monolith (4). During machining, a carbide insert is applied to the hole to avoid wear on the steel and to form a pivot point (5).

[0008] The strength and ductility of the substrate are generally considered in relation to the applied stress of the application. Examples of substrate materials include titanium, aluminum, and steel. Steel is often used in a heat-treated state and can have a tensile strength of approximately 100,000 to 200,000 psi. Alloying and different treatments result in increased strength. Most metal substrates are also ductile and undergo plastic deformation before failure.

[0009] Cladding or coatings utilize hard phases such as tungsten carbide, boron nitride, and chromium carbide. Other combinations include metals with oxides, borides, nitrides, and carbides. When such hard phases are added to a coating, their volume in the resulting surface-strengthened composite is limited by the application method. Typically, a range of about 40% to 50% is observed. This is a relatively low content compared to sintered composites and filled liquid metal impregnation composites, which range from about 65% to 95%.

[0010] Liquid metal impregnation: Liquid metal impregnation has been used for either self-supporting monoliths or substrate-backed monoliths. The basic process is as follows: 1. Formation of the powder bed 2. Melting of the binder that will later come into direct or indirect contact with the powder bed. 3. Allow sufficient time for the binder to wet the powder bed and fill the voids within the powder bed by capillary action. 4. Cooling of the binder for the metal matrix composite to below the solidus.

[0011] The powder bed (1) can be formed using a binder and then formed by pressing or placing using additive manufacturing to form a green body. Such a binder is lost, evaporated, or burned out during subsequent heating of the part. Examples of binders can include polyethylene glycol, wax, paraffin, or cellulose-based materials. Typically, and more simply, a mold is formed and filled with powder. The powder can be metal, ceramic, or cermet and generally forms a hard phase within the resulting composite. If a combination of strength and wear resistance is required, the powder can be formed from crushed tungsten carbide or spherical cast tungsten carbide or a combination thereof. The mold itself and any fixture having the mold inside can be made from hard carbon, ceramic, sand, and steel. The mold parts can be machined, formed by additive manufacturing, created using a lost wax process, or processed using a resin that cures during moderate heating or cures under a gas such as carbon dioxide. Internal or external parts can be added within or near the powder bed to form a substrate.

[0012] A binder or infiltrant (2) can form a molten bath and the powder bed (1) is placed in contact with it or fully immersed. In another technique typically seen in the manufacture of drill bit bodies, an infiltrant is placed on the powder and the part is heated throughout so that the binder melts and forms a metal matrix composite upon cooling.

[0013] In some cases, the powder can be placed in a mold, an infiltrant placed on top, and a positive pressure can be applied before, during, and / or after infiltration (preferably throughout). In some cases, the powder is consolidated by hand tapping or vibratory compaction to maximize the hard phase content.

[0014] When the infiltrant becomes a liquid, in part (3), a complete infiltration path is created according to the wettability, excess heat amount, hydrostatic pressure, and immersion time between the hard phase and the infiltrant. The time sufficient for complete infiltration can be determined by those skilled in the art using this specification as a guide and depends on the materials used and the articles to be manufactured. For example, for test coupons and small articles, an infiltration time of 15 minutes may be sufficient. Larger articles such as machine parts generally take longer times, such as about 1 hour. Cooling (4) can be performed by directional cooling through a fan or a water jet in still air. Thereby, a metal matrix composite is created after solidification.

[0015] In another example, liquid metal infiltration is used to form parts. The bearings used in downhole motors are formed using steel molds. An annular space is formed between the two parts. This void is filled with metal powder and compressed and solidified. A binder is placed on the powder and the part is heated by an induction coil or the like. After cooling, a metal matrix composite is obtained.

[0016] Figure 1 shows a known configuration of a liquid metal infiltration process. The porous medium 101 is arranged in contact with either a liquid infiltrant 102 or a solid infiltrant 103. The porous medium can be partially immersed in the liquid infiltrant (Figure 1a), or completely immersed (Figure 1b), or the solid infiltrant can be placed in contact with the porous medium (Figure 1c).

[0017] Metal matrix composites formed by liquid metal infiltration offer a much simpler manufacturing method for creating self-supporting or substrate-backed monoliths compared to those created using multi-stage carbide sintering operations. Conventional metal matrix composites generally do not compare favorably to sintered carbide tungsten carbide and substrate-clad components because the combination of properties of the metal matrix composite is compromised and generally inferior. These deficiencies include, but are not limited to, strength, ductility, plasticity, wear resistance, fracture toughness, and thermal shock resistance. Typical metal matrix composites exhibit little to no ductility and are classified as brittle materials. During testing, little to no plastic deformation occurs, linear elastic behavior is observed, and then instantaneous fracture occurs. Strength is generally limited to a maximum of approximately 160,000 psi when bending tests are performed. Reliability is limited by defect statistics and the overall strength of the composite, as determined using Weibull statistics. Typically, a Weibull coefficient of about 20 is achieved. This often limits their use in many engineering applications. Typically, liquid metal osmosis is carried out at temperatures below 1180°C.

[0018] The mechanical properties of metal matrix composites are typically inferior to those of typical clad substrates. The surface wear properties of the substrate may not be satisfactory for the environment in which it operates, resulting in insufficient corrosion resistance, wear resistance, and erosion resistance, for example. Therefore, coating or cladding is necessary.

[0019] While the manufacturing method using liquid metal impregnation is well known, its applications are generally limited to drill bits and bearings.

[0020] Utilizing a simple method of liquid metal impregnation to form monoliths or substrate-backed components with strength and ductility is advantageous because it offers a remarkably attractive alternative to conventional engineering substrates such as steel. Combining this with coated or clad substrates and wear resistance comparable to sintered tungsten carbide components opens the door to novel and unexpected applications for liquid metal impregnation composites. [Overview of the project]

[0021] A cast tungsten carbide powder is provided, comprising granules having a grain interface integral ratio of 20% to 50% and an average aspect ratio of less than 1.3. Also provided is a heat-treated cast tungsten carbide powder, prepared by heating the above-mentioned tungsten carbide powder to a temperature of 1000 to 1250°C, preferably 1100 to 1250°C or 1190 to 1250°C, for 0.5 to 50 hours under vacuum or a non-reactive atmosphere, prior to liquid metal infiltration to form a metal matrix composite. This conversion results in the formation of metallic tungsten within the cast tungsten carbide particles.

[0022] Alternatively, a conversion and property improvement of tungsten carbide powder is provided, comprising granules having a particle interface integral ratio of 20% to 50%, an average aspect ratio of less than 1.3, and a carbon content of 3.0 to 4.5% by weight. This conversion is provided during liquid metal infiltration, in which the tungsten carbide powder is in contact with a liquid metal at a temperature of 1000 to 1250°C, preferably 1190 to 1250°C, for 0.5 to 50 hours.

[0023] The conversion of the properties of cast tungsten carbide either before or during liquid metal infiltration forms 1 to 50% by weight, preferably 5 to 50% by weight, and most preferably 10 to 50% by weight of tungsten metal phase within the cast tungsten carbide particles. The particles may or may not contain a hemispherical carbide (W2C) phase. The resulting particles exhibit increased toughness, thermal conductivity, and thermal shock resistance compared to unconverted particles. These desirable properties are, in turn, transferred to the resulting metal matrix composite.

[0024] Some specific preferred embodiments include, for example, a cast tungsten carbide powder comprising a tungsten carbide (monocarbide) phase and a metallic tungsten phase which may or may not include a hemispherical carbide (W2C) phase.

[0025] In the embodiment, the powder contains metallic tungsten phase in a proportion of 1 to 10% by weight or more, preferably 11 to 20% or more, and most preferably 21 to 50% or more.

[0026] The tungsten carbide powder, which may be heat-treated tungsten carbide powder, preferably has a carbon content of 3.0 to 4.5% by weight.

[0027] A composition comprising tungsten carbide powder and an alloy containing 50-85% by weight of copper is also provided.

[0028] Furthermore, a method for manufacturing a metal matrix composite article is also provided, which comprises: obtaining cast tungsten carbide powder containing converted cast tungsten carbide powder; heating the cast tungsten carbide powder in the presence of a binder alloy at a temperature and time sufficient to cause the binder alloy to melt and penetrate the cast tungsten carbide powder to form a permeated article; and obtaining a metal matrix composite article by cooling the permeated article to solidify the binder alloy, wherein the heat-treated tungsten carbide The tungsten carbide powder is prepared by heating tungsten carbide raw material powder having an aspect ratio of less than 1.3 and containing needle-like structures on its surface, under vacuum, in a non-reactive atmosphere, or in air, at a temperature of 1000 to 1250°C, preferably 1100 to 1250°C or 1190 to 1250°C, for 0.5 to 50 hours. The cast tungsten carbide powder contains at least 10% by weight of converted heat-treated tungsten carbide powder based on the total carbide in the tungsten carbide powder, and the binder alloy contains 50 to 85% by weight of copper.

[0029] Alternatively, during a liquid metal process, cast tungsten carbide particles can be converted to up to 50% by weight of tungsten by ensuring that the liquid phase is in contact with these particles for 0.5 to 50 hours at 1000 to 1250°C, preferably 1190 to 1250°C.

[0030] In the manufacturing method, it is preferable that the heat-treated tungsten carbide powder contains granules having a particle interface integral ratio of 20% to 50% and an average aspect ratio of less than 1.3. In the manufacturing method, it is preferable that the heat-treated tungsten carbide powder has a surface undulation shape including needle-like structures having an aspect ratio of less than 1.3. In the manufacturing method, it is preferable that the heat-treated tungsten carbide powder has a surface undulation shape including needle-like structures having an aspect ratio in the range of 1 to 1.3.

[0031] Furthermore, metal matrix composite articles prepared by this manufacturing method are also provided.

[0032] Also provided are metal matrix composite articles containing cast tungsten carbide particles in an alloy matrix, wherein the cast tungsten carbide particles consist of 10% to 100% by weight of heat-treated tungsten carbide particles based on the total weight of the tungsten carbide particles, the heat-treated tungsten carbide particles are heated to a temperature of 1000 to 1250°C, preferably 1100 to 1250°C or 1190 to 1250°C, for 0.5 to 50 hours under vacuum or a non-reactive atmosphere, the tungsten carbide particles or heat-treated tungsten carbide particles have an aspect ratio of 1 to 1.3, and the alloy matrix contains 50 to 85% by weight of copper.

[0033] Furthermore, during the liquid metal infiltration process, the cast tungsten carbide is heat-treated in situ while in contact with the liquid metal to form MMC at an infiltration temperature of 1000-1250°C, preferably 1190-1250°C, and an immersion time of 0.5-50 hours.

[0034] The metal matrix composite article, when measured according to ASTM G65, is 6 mm 3The following wear resistance is preferable: The metal matrix composite article preferably exhibits a volume loss of 0.8 cc or less when measured according to ASTM B611. The metal matrix composite article preferably exhibits a Charpy impact toughness of at least 6.75 J.

[0035] In some embodiments, the metal matrix composite article includes tungsten carbide particles having a D50 of 1 μm to 10 μm and a TRS of 360 ksi or higher. In some embodiments, the metal matrix composite article includes tungsten carbide particles having a D50 of 11 μm to 20 μm and a TRS of 280 ksi or higher. In some embodiments, the metal matrix composite article includes tungsten carbide particles having a D50 of 21 μm to 40 μm and a TRS of 230 ksi or higher. In some embodiments, the metal matrix composite article includes tungsten carbide particles having a D50 of 41 μm to 60 μm and a TRS of 180 ksi or higher. In some embodiments, the metal matrix composite article includes tungsten carbide particles having a D50 of 61 μm to 80 μm and a TRS of 160 ksi or higher. In some embodiments, the metal matrix composite article includes tungsten carbide particles having a D50 of 81 μm to 100 μm and a TRS of 140 ksi or higher. In some embodiments, the metal matrix composite article includes tungsten carbide particles having a D50 of 111 μm to 200 μm and a TRS of 100 ksi or higher. In some embodiments, the metal matrix composite article includes tungsten carbide particles having a D50 of 201 μm to 500 μm and a TRS of 80 ksi or higher. In some embodiments, the metal matrix composite article includes tungsten carbide particles having a D50 of 501 μm to 1000 μm and a TRS of 60 ksi or higher. In some embodiments, the metal matrix composite article includes tungsten carbide particles having a D50 of 1001 μm to 2000 μm and a TRS of 50 ksi or higher.

[0036] In some embodiments, the metal matrix composite article contains different composites in different areas of the component to provide desired properties during use. [Brief explanation of the drawing]

[0037] [Figure 1] A known configuration of a liquid metal impregnation process is shown. The porous medium may be partially immersed in the liquid impregnating agent (Figure 1a), completely immersed in the liquid impregnating agent (Figure 1b), or a solid impregnating agent may be placed in contact with the porous medium (Figure 1c). [Figure 2] Figure 2a shows an example component made from a base cladding component in which a WC layer 202 is coated on a steel component 203, and Figure 2b shows an example component made from a carbide WC component in which the entire component is made from carbide WC. [Figure 3] An example drawing of a bottle opener made of two composite materials is shown. [Figure 4] This is an SEM image of a conventional metal powder with angular particles. [Figure 5] This is an optical microscope image of a conventional MMC prepared using angular particles. [Figure 6] This is an optical microscope image of MMC prepared using spherical particles. [Figure 7] This is a conventional SEM image of spherical carbide. [Figure 8] This disclosure shows an SEM image of spherical carbide processed to a rough surface. [Figure 9] This is the binary image shown in Figure 7. [Figure 10] This is the binary image shown in Figure 8. [Figure 11] The images provide photographs of Vickers indentation on WC particles in MMC articles when the WC powder is not heat-treated (Figures 11a to 11d) and when the WC powder is heat-treated (Figures 11e to 11h). [Figure 12]This shows a comparison of the sliding distance between a medium-grain cemented tungsten carbide with 10% cobalt added and a component impregnated with heat-treated spherical cast tungsten carbide, after an ASTM B611 abrasion test. [Modes for carrying out the invention]

[0038] This specification discloses embodiments of permeation components that meet or exceed the performance attributes of sintered WC components and clad substrates. In contrast to the typical laborious methods used to manufacture sintered WC components and clad substrates, this disclosure provides permeation processes. A series of efforts are described that can move lower-cost permeation processes (technologies currently available for drill bits and bearings) to a performance regime that is comparable to and exceeds the properties of sintered components, clad substrates, and the substrates themselves.

[0039] The present invention is applicable to a wide variety of applications and industries. Figure 2 provides two non-limiting exemplary examples of base material cladding components. In Figure 2b, part of the component is a WC layer 202 cladded onto part 203 (e.g., steel). Figure 2b shows a component entirely made from carbide WC. The exemplary base material cladding component in Figure 2a is a retractable pad used in rotary maneuverable tools in the oil and gas industry. The exemplary carbide WC component in Figure 2b is a fracking valve seat, also used in the oil and gas industry. The permeation components described herein can be used to produce both exemplary components that replace current manufacturing methods. In the case of a part cladded with a WC-containing layer (e.g., the retractable pad in Figure 2a), it will be understood that the permeation components can be used to produce not only the cladding layer but the entire component, thereby replacing all or part of the component (e.g., the steel portion).

[0040] In some embodiments of the present invention, preferably, certain processes common to the production of cemented carbide WC are avoided. In some embodiments, the infiltration component is preferably made without sintering and / or hot isostatic pressing. In some embodiments, the infiltration component is preferably made without welding processes such as MIG, TIG open arc welding, PTA, and / or laser cladding. In some embodiments, the infiltration component is preferably made without any spraying processes such as TWAS, HVOF, and / or plasma spraying. In some embodiments, the infiltration component is preferably made without any deposition processes such as CVD and PVD.

[0041] In some embodiments, the component is used for wear-resistant parts and is characterized by high wear resistance quantified by the dry sand abrasion test of ASTM G65 and / or the high-stress abrasion test of ASTM B611. In some embodiments, the volume loss of the component according to ASTM G65 is 6 mm 3 or less, 5 mm 3 or less, 4 mm 3 or less, or 3 mm 3 or less. The volume loss of the component according to ASTM G65 is generally 0 mm 3 or more, 1 mm 3 or more, 2 mm 3 or more, or 3 mm 3 or more. The ranges formed from these values (including or excluding the endpoints), for example, ASTM G65 volume loss 0 mm 3 ~6 mm 3 、0 mm 3 ~5 mm 3 、0 mm 3 ~4 mm 3 、0 mm 3 ~3 mm 3 、1 mm 3 ~6 mm 3 、2 mm 3 ~6 mm 3 、3 mm 3 ~6 mm 3 、and 1 mm 3 ~5 mm 3 are also included.

[0042] High stress wear tests measured according to ASTM B611 typically measure volume loss in cubic centimeters (cc). ASTM B611 volume loss is preferably 0.8 cc, 0.75 cc, or 0.65 cc or less. ASTM B611 volume loss is preferably 0 cc, 0.05 cc, 0.1 cc, 0.2 cc, 0.4 cc, or 0.45 cc or more. The ranges formed from these values ​​(with or without the endpoints) are also included, for example, less than 0.8 cc, 0.8 cc or less, less than 0.75 cc, 0.75 cc or less, less than 0.65 cc, 0.65 cc or less, 0.8 to 0.05 cc, 0.75 to 0.1 cc, 0.65 to 0.1 cc, and 0.05 to less than 0.8 cc.

[0043] In this disclosure, the size of the spherical cast tungsten particles used in the components may be in the range of 1 to 2000 μm, or in the range of approximately 1 to 200 μm. Variations in the size of the spherical cast tungsten particles may affect the transverse rupture strength (TRS) of the final impregnated MMC. The transverse rupture strength (TRS) is measured by applying a central force to a cylindrical rod. The tensile stress generated under the applied force increases until fracture occurs. The fracture stress is calculated from the applied force and the geometry of the test specimen rod. Such techniques are described in detail in ASTM B406 for small cubic test specimens commonly used to measure the TRS of cemented tungsten carbide. For liquid metal impregnated components, internal standards using cylinders are often applied.

[0044] Determining the particle size distribution of a powder is well within the capabilities of those skilled in the art, and such persons will be familiar with the apparatus and methods for doing so. One preferred method involves the use of laser light scattering, such as a MicroTrac device according to ASTM B822, which is incorporated herein by reference in whole. From various points on the curve obtained by this method, various measurements of particle size can be determined. Three such points include: -D10 or 10th percentile particle size (μm), -D50 or average particle size (μm), and -D90 or 90th percentile particle size (μm).

[0045] Unless otherwise specified, particle size in this specification generally refers to the average particle size D50. As a general issue, the choice of particle size for tungsten carbide powder can affect the properties of MMC articles made from the powder. For example, as is known in the art, all other conditions being equal, there is an inverse correlation between the particle size of carbide powder and the strength of the component. Therefore, components made from finer (smaller D50) carbide powder tend to exhibit greater strength than components made from coarser (larger D50) carbide powder. On the other hand, smaller particle sizes can lead to lower toughness, as in cemented tungsten carbide, larger particles result in higher toughness. The D50 of the tungsten carbide particles to be selected generally depends on the specific intended application and can be chosen as needed by those skilled in the art. Not one particle size is suitable for all applications.

[0046] Therefore, tungsten carbide particles are available in a wide range of particle sizes for various applications. Some tungsten carbide particle sizes include 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 120 μm, 140 μm, 160 μm, 180 μm, 200 μm, 250 μm, 500 μm, 1000 μm, and 2000 μm, all of which can be increased or decreased by 1 μm. Ranges formed by any two of these values ​​(with and without endpoints), for example, 1 μm to 10 μm, 10 μm or 11 μm to 20 μm, 11 μm to 20 μm, 20 μm to 40 μm, 21 μm to 39 μm, 40 μm to 60 μm, 60 μm to 80 μm, 80 μm to 100 μm, and 100 μm to 200 μm, 200 μm to 500 μm, 500 μm to 1000 μm, and 1000 μm to 2000 μm are also intended.

[0047] In some embodiments, components made from spherical cast tungsten carbide particles having an average particle size (D50) of 1 μm to 10 μm have a TRS of 360 ksi (or about 360 ksi) or more, 530 ksi (or about 530 ksi) or more, or 700 ksi (or about 700 ksi) or more. Higher TRSs are also intended. In practice, the TRS is generally less than 1000 ksi.

[0048] In some embodiments, components made from spherical cast tungsten carbide particles having an average particle size (D50) of 11 μm to 20 μm have a TRS of 280 ksi (or about 280 ksi) or higher, 365 ksi (or about 365 ksi) or higher, or 450 ksi (or about 450 ksi) or higher. Higher TRSs are also intended. In practice, the TRS is generally less than 700 ksi.

[0049] In some embodiments, components made from spherical cast tungsten carbide particles having an average particle size (D50) of 21 μm to 40 μm have a TRS of 230 ksi (or about 230 ksi) or higher, 260 ksi (or about ksi) or higher, or 290 ksi (or about 290 ksi) or higher. Higher TRSs are also intended. In practice, the TRS is generally less than 450 ksi.

[0050] In some embodiments, components made from spherical cast tungsten carbide particles having an average particle size (D50) of 41 μm to 60 μm have a TRS of 180 ksi (or about 180 ksi) or more, 200 ksi (or about 200 ksi) or more, or 220 ksi (or about 220 ksi) or more. Higher TRSs are also intended. In practice, the TRS is generally less than 350 ksi.

[0051] In some embodiments, components made from spherical cast tungsten carbide particles having an average particle size (D50) of 61 μm to 80 μm have a TRS of 160 ksi (or about 160 ksi) or higher, 170 ksi (or about 170 ksi) or higher, or 180 ksi (or about 180 ksi) or higher. Higher TRSs are also intended. In practice, the TRS is generally less than 300 ksi.

[0052] In some embodiments, components made from spherical cast tungsten carbide particles having an average particle size (D50) of 81 μm to 100 μm have a TRS of 140 ksi (or about 140 ksi) or more, 150 ksi (or about 150 ksi) or more, or 160 ksi (or about 160 ksi) or more. Higher TRSs are also intended. In practice, the TRS is generally less than 250 ksi.

[0053] In some embodiments, components made from spherical cast tungsten carbide particles having an average particle size (D50) of 101 μm to 200 μm have a TRS of 100 ksi (or about 100 ksi) or more, 120 ksi (or about 120 ksi) or more, or 140 ksi (or about 140 ksi) or more. Higher TRSs are also intended. In practice, the TRS is generally less than 200 ksi.

[0054] In some embodiments, components made from spherical cast tungsten carbide particles having an average particle size (D50) of 201 μm to 500 μm have a TRS of 80 ksi (or about 80 ksi) or higher, 90 ksi (or about 90 ksi) or higher, or 95 ksi (or about 95 ksi) or higher. Higher TRSs are also intended. In practice, the TRS is generally less than 100 ksi.

[0055] In some embodiments, components made from spherical cast tungsten carbide particles having an average particle size (D50) of 501 μm to 1000 μm have a TRS of 60 ksi (or about 60 ksi) or more, 70 ksi (or about 70 ksi) or more, or 75 ksi (or about 75 ksi) or more. Higher TRSs are also intended. In practice, the TRS is generally less than 80 ksi.

[0056] In some embodiments, components made from spherical cast tungsten carbide particles having an average particle size (D50) of 1001 μm to 2000 μm have a TRS of 50 ksi (or about 50 ksi) or more, and 55 ksi (or about 55 ksi) or more. Higher TRSs are also intended. In practice, the TRS is generally less than 60 ksi.

[0057] In some embodiments, the novel metal matrix composites are characterized by high toughness. Charpy impact testing is a typical method for evaluating the toughness of materials, and the toughness of the disclosed components was quantified using unnotched Charpy impact specimens. In some embodiments, the Charpy impact toughness exceeds 5.0 ft·lbf (or 6.75 or 6.8 J), in preferred embodiments the toughness exceeds 6.0 ft·lbf (or 8 or 8.1 J), in more preferred embodiments the toughness exceeds 8.0 ft·lbf (or 10.75 or 10.8 J), and even more preferably the components have toughness exceeding 9.0 ft·lbf (or 12 or 12.2 J), 10.0 ft·lbf (or 13.6 or 14 J), or 11.0 ft·lbf (or 14.9 or 15 J). While there is no preferred upper limit for toughness, in practice, Charpy impact toughness is generally less than 20.0 ft·lbf (or 27 or 27.1 J). Charpy impact toughness can be measured according to ASTM E23, without a V-notch, or by another suitable method.

[0058] Enhanced toughness is a key performance attribute that makes the disclosed components more suitable for typical applications than cemented tungsten carbide components. Enhanced toughness, combined with strength, is not common in typical components fabricated by impregnation processes. For example, industry-leading impregnation components used in the drill bit industry, including Cu53 copper binder and angular WC binder, exhibit a toughness of 3.3 ft·lbf (or 4.47 or 4.5 J) in equivalent notched Charpy impact tests. By utilizing spherical WC particles, toughness can be increased to 5.9 ft·lbf or 8.0 J. By utilizing the novel binder described herein in combination with spherical carbide processed to a rough surface, toughness can be further increased to 9.2 ft·lbf or 12.5 J. When spherical cast tungsten carbide particles are heat-treated at 1000-1250°C, preferably 1190-1250°C, for 0.5-50 hours, the toughness is again improved to 13.7 ft·lbf or 18.6 J. Therefore, the component technology described herein increases toughness by as much as 315% compared to the technology currently used with Cu53 copper-based binders and angular WC. This dramatic increase makes it possible to use the disclosed technology in structural components typically reserved for cemented tungsten carbide components.

[0059] In some embodiments, components can be described by the components used to produce the final component. In the impregnation process, carbide powder is placed in a mold of a suitable material, typically graphite. Furthermore, the mold is usually vibrated after the carbide is introduced to allow it to settle. A metal alloy, typically a copper-based alloy, is placed on top of the carbide powder. The assembly is introduced into a furnace to melt the copper and impregnate it into the empty spaces in the carbide powder. Upon cooling, the assembly becomes a solid component in which the copper alloy and carbide powder are strongly bonded to each other. In one embodiment of the present invention, the carbide powder is tungsten carbide (WC) powder. In a preferred embodiment, the carbide powder has a roughened surface as opposed to a smooth surface. In another preferred embodiment, the carbide powder is spherical. In a further preferred embodiment, the carbide powder is spherical WC with a roughened surface. In another preferred embodiment of the present invention, the tungsten carbide is heat-treated before being introduced into the impregnation process. In yet another preferred embodiment of the present invention, tungsten carbide is heat-treated in situ during a liquid metal infiltration process to an infiltration temperature of 1000-1250°C, preferably 1190-1250°C or 1190-1250°C, and an immersion time of 0.5-50 hours to form MMC. In another embodiment, a high copper binder alloy is used.

[0060] In another embodiment, inserts are used to form the desired final shape of the component. In some embodiments, these inserts are 3D printed. These inserts may be ceramic (such as alumina or silicon carbide), sand (such as quartz or ceramic beads), or plastic. In some embodiments, these 3D printed sand inserts are placed in a graphite container which may have a base, sides, and a lid. The assembly of the sand or ceramic mold and graphite further comprises a porous molded body and a binder material, and this assembly can be heated to induce a penetration process and form the MMC composite into the desired shape.

[0061] In another embodiment, different materials are used in different locations within the mold and the resulting part. For example, a material with finer particles provides strength, while a material with coarser particles improves wear resistance. Figure 3 shows an example drawing of a bottle opener having two composite materials. In Figure 3, composite material A has high wear resistance, while composite material B exhibits high strength. In some embodiments, the penetrating component consists of a region having high strength and another region having high wear resistance. The high-strength region has a D50 of 1 to 100 μm, a TRS of 140 to 1000 ksi, and an ASTM B611 volume loss of 0.65 to 0.80 cc. The high-wear-resistant region has an ASTM B611 volume loss of 0.10 to 0.65 cc, a D50 of 100 to 2000 μm, and a TRS of 50 to 140 ksi. In some other embodiments, the infiltration component comprises a region having unheat-treated tungsten carbide and another region in which 10 to 100% by weight of the total weight of tungsten carbide in that region is heat-treated tungsten carbide. In yet another embodiment, the infiltration component comprises several regions having different proportions of heat-treated tungsten carbide. For example, one region of the infiltration component contains 40% by weight of heat-treated tungsten carbide. Another region of the infiltration component contains 100% by weight of heat-treated tungsten carbide. Yet another region of the infiltration component contains 0% by weight of heat-treated tungsten carbide.

[0062] Forms of carbide powder: In some embodiments of the present invention, the component carbide has a spheroidal morphology. The spheroidal carbide for use according to this disclosure may be prepared from a carbide powder, such as the one disclosed in International Publication No. 2021 / 173515 (which is incorporated herein in its entirety), and may be used.

[0063] Spheroidal or substantially spherical molten tungsten carbide particles can generally be produced from ordinary molten tungsten carbide powder or a mixture of tungsten, monotungsten carbide, and / or carbon. In some embodiments, spheroidal or substantially spherical molten tungsten carbide particles may have a composition of 3.7–4.2 (or about 3.7–4.2) wt% carbon and the remainder tungsten. The particles can be produced by many methods. In some methods, a mixture of tungsten powder blended with monotungsten carbide and carbon powder is first melted. The molten mixture is then pulverized by a rotational pulverization process or an ultra-high temperature melting and pulverization process. These processes spheroidize the molten tungsten carbide into spheroidal or substantially spherical molten tungsten carbide particles by surface tension during a rapid solidification process. Other methods may be based on the modification of ordinary molten tungsten carbide powder. During the spheroidization process, plasma spraying, electric induction, or electric resistance furnace melting is applied to obtain fine spheroidal or substantially spherical molten tungsten carbide particles.

[0064] As described herein, “sphericity” can be defined by the aspect ratio of a spheroidal or substantially spherical particle. The aspect ratio may be the ratio of a first length along the major axis to a second length along the minor axis, or the ratio of the longest axial length to the shortest axial length, for a spheroidal or substantially spherical particle. For example, a “perfectly” spherical particle has an aspect ratio of exactly 1.0. On the other hand, an “angular” particle as described above in the art has an aspect ratio of at least 1.30.

[0065] In embodiments of this disclosure, the spheroidal or substantially spherical molten tungsten carbide particles disclosed herein may have an aspect ratio of 1.30 (or about 1.30) or less. In some embodiments, spherical molten tungsten carbide may have an aspect ratio of 1.20 (or about 1.20) or less. In some embodiments, spherical molten tungsten carbide may have an aspect ratio of 1.10 (or about 1.10) or less. In some embodiments, spherical molten tungsten carbide may have an aspect ratio of 1.05 (or about 1.05) or less. The aspect ratio may also be within the range defined by any two of these values. The aspect ratios disclosed herein may represent the average value of the aspect ratios of a plurality of molten tungsten carbide particles. In some embodiments, each particle may have an aspect ratio as disclosed herein. Some upper limits for the aspect ratio include 1.3, 1.2, 1.1, and 1.05. Lower limits include 1.2, 1.1, and 1.05, with the lowest understood value being 1. A range formed by any two of these values ​​(inclusive and exclusive of the endpoints), e.g., less than 1.3, 1.3 or less, less than 1.2, 1.05 to 1.3, 1 to 1.05 (or equivalently, "maximum 1.05" or "less than or equal to 1.05"), is also intended.

[0066] The aspect ratio can be determined by a person skilled in the art by any suitable method. For example, the aspect ratio can be determined from a visual or computer-aided analysis of a micrograph of tungsten carbide powder.

[0067] The specific gravity of molten tungsten carbide powder in the shape of a spheroid or substantially spherical form is approximately 16.5 g / cm³. 3While possible, the microhardness is advantageously in the range of 2,700–3,300 HV (or about 2,700–about 3,300 HV). These properties may be due, among other things, to the particle shape and internal microstructure resulting from the ellipsoidal formation process described above. In other embodiments, lower hardness tungsten carbides with hardness in the range of 1,900–2,300 HV are used, but the decrease in hardness is due to heat treatment. Generally, MMCs containing ellipsoidal or substantially spherical molten tungsten carbide particles have higher wear resistance than those containing angular molten tungsten carbide for particles of comparable size and fraction. Below, we will describe the various microstructural differences between conventional angular tungsten carbide particles and MMCs formed therefrom and ellipsoidal or substantially spherical tungsten carbide particles and MMCs formed therefrom according to embodiments.

[0068] Figure 4 shows a scanning electron microscope (SEM) image of a conventional metal powder. As shown in the figure, the powder is angular.

[0069] Figure 5 is an optical micrograph of a conventional MMC prepared using known metallographic techniques. As shown, the MMC comprises a soft phase 501, a particulate phase 502 (formed from powder similar to that shown in Figure 4), and an interface 503 between the particulate phase and the soft phase. The soft phase may be formed from a matrix material that is first melted and then cooled. Thus, the MMC in Figure 5 comprises two main phases, with the soft phase 501 formed by liquid metal infiltration of the particulate phase 502.

[0070] The particulate phase may include metal carbides, borides, or oxides. For example, the particulate phase may include tungsten carbide, which includes monotungsten carbide, molten tungsten carbide, and / or cemented tungsten carbide. Tungsten carbide particles are typically angular, as shown in Figure 4. An interface exists between the soft phase and the particulate phase. As described herein, the inventors unexpectedly discovered that all three can contribute to the strength and wear properties of the MMC.

[0071] Figure 6 shows an optical micrograph of a metal matrix composite (MMC) 20 prepared using spheroidal or substantially spherical carbide particles according to an embodiment. As shown, the MMC 20 comprises spheroidal or substantially spherical molten tungsten carbide particles 4 and a soft phase 5, which are combined to form the metal matrix composite (MMC) 20. The MMC 20 further includes a spheroidal or substantially spherical molten tungsten carbide-soft phase interface 6.

[0072] The interface 6 includes metallic or metallurgical bonds formed between the tungsten carbide particles 4 and the soft phase 5. It will be understood that the metallurgical bonds disclosed herein may include diffusing atoms and / or interatomic interactions, and may include chemical bonds formed between the atoms of the particles 4 and the atoms of the soft phase. The metallurgical bonds are more than mere mechanical bonds. Under such conditions, the components may be "wetted" to and by the metallic bonding material.

[0073] Surface morphology of carbide particles: In some embodiments of the present invention, the carbide components have a uniquely roughened surface morphology.

[0074] In this disclosure, the surface relief shape of spheroidal or substantially spherical molten tungsten carbide particles forming the powder was investigated in detail. A novel surface state of spheroidal or substantially spherical molten tungsten carbide is a roughened surface. As shown in Figure 6, the inventors found that this roughened surface can increase the available surface area at the interface 6 between the soft phase 5 and the spheroidal or substantially spherical molten tungsten carbide particles 4.

[0075] Figure 7 shows the surface morphology of tungsten particles in a conventional MMC. As shown, the microstructure has the "soccer ball-like" undulating shape characteristic of conventional molten tungsten carbide particles. The surface is relatively smooth, resulting in a low surface area and relatively low interfacial strength when incorporated into an MMC.

[0076] The strength of an MMC system can depend on one or more of three different components: 1) the strength of the copper binder, 2) the strength of the tungsten carbide particles, and 3) the bonding strength between the copper binder and the incorporated tungsten carbide particles. Therefore, if the tungsten carbide particles and copper do not bond sufficiently, the MMC may break under high stress. By having carbide particles with a larger surface area, the alloy has a larger surface area for bonding to the carbide particles, thus substantially increasing the interfacial strength.

[0077] Figure 8 shows the surface morphology of spheroidal or substantially spherical tungsten particles in an MMC according to an embodiment of the present disclosure. As shown, the microstructure includes "needle-like" undulation features (e.g., rough surface treatment) of the spheroidal or substantially spherical molten tungsten carbide. The surface is roughly processed with a predominantly fine-grained structure, resulting in a high surface area and better interfacial strength when incorporated into the MMC.

[0078] To quantify spheroidal or substantially spherical molten tungsten carbide particles based on their surface characteristics, the fraction of surface area in a fixed field of view of an optical or SEM image, which may be attributable to grain boundaries, is analyzed. As described herein, the grain boundary area fraction refers to the area in an image, e.g., an optical or SEM image, of the surface of a sample, e.g., the surface of tungsten carbide particles, which may be attributable to grain boundaries. The grain boundary area fraction can be quantified using an image, e.g., a high-contrast or binary image, such as those shown in Figures 9 and 10. For example, the number of dark pixels as a fraction of the total number of pixels in the imaged field of view can correspond to the grain boundary area fraction. The inventors have found that the conventional “soccer ball” surface morphology of tungsten carbide particles results in a relatively low grain interface integral ratio on the surface of the tungsten carbide particles, e.g., less than 5%. On the other hand, tungsten carbide particles with a “needle-like” surface morphology have a relatively high grain interface integral ratio on the surface of the tungsten carbide particles, e.g., more than 10% (or about 10%).

[0079] For example, the grain boundary area fraction in Figure 7 is 3.6%, and the value in Figure 8 is 14.2%. Figure 9 is a binary image of Figure 7. Figure 10 is a binary image of Figure 8, which, when divided into nine parts, includes an analytical area fraction of 14.2% and a variation of 9.4.

[0080] For an object of a given volume, a sphere has the mathematically smallest possible area-to-volume ratio. Therefore, spherical carbide particles are expected to have a low grain interface integral ratio. However, the inventors have discovered that the needle-like surface morphology of tungsten carbide particles results in an unexpectedly high surface area, which in turn leads to a high grain interface integral ratio. This makes it possible to provide tungsten carbide particles that are spherical and have a large grain boundary area. A high grain interface integral ratio can be proportional to the amount of high-strength interface formed between the tungsten carbide particles and the metal matrix, and consequently, to the mechanical and frictional properties of the MMC, including TRS and corrosion resistance.

[0081] Furthermore, according to some embodiments, the needle-like ridge shape includes needle-like structures extended along the surface of tungsten carbide particles. The needle-like structures have at least one length portion having a length greater than, for example, 0.5, 1, 2, 3, 4, or 5 μm, or a value within the range defined by any two of these values, while having a width less than 2, 1, 0.5, 0.2, or 0.1 μm, or a value within the range defined by any two of these values. The needle-like structures may have an aspect ratio of the longest length to the minimum width greater than 2, 5, 10, or 20, or a value within the range defined by any two of these values.

[0082] In some embodiments, spheroidal or substantially spherical molten tungsten carbide particles may have a grain interface integral ratio of 5.0% (or about 5.0%) or higher. In some embodiments, spheroidal or substantially spherical molten tungsten carbide particles may have a grain interface integral ratio of 10.0% (or about 10.0%) or higher. In some embodiments, spheroidal or substantially spherical molten tungsten carbide particles may have a grain interface integral ratio of 12.0% (or about 12.0%) or higher. In some embodiments, spheroidal or substantially spherical molten tungsten carbide particles may have a grain interface integral ratio of 12.0% (or about 12.0%) or higher. In some embodiments, spheroidal or substantially spherical molten tungsten carbide particles may have a grain interface integral ratio of 20.0% (or about 20.0%) or higher. The grain interface integral ratio may also be within the range defined by any two of these values.

[0083] Furthermore, the grain boundary area fraction of the carbide powder, preferably spheroidal powder, is preferably 5%, 10%, 14%, 15%, 20%, or 25% or more. There is no preferred upper limit for the grain interface integral fraction, but it is generally 50%, 40%, or 30% or less. Ranges formed by any two of these values ​​(with and without endpoints), for example, 5%~50%, 10%~40%, 5%~40%, 5%~30%, 10%~50%, 10%~40%, 10%~30%, 10%~25%, 10%~20%, 14%~60%, and 14%~30% are also intended.

[0084] Tungsten carbide conversion: In some embodiments of the present invention, the components include carbide that is heat-treated before or during the penetration process. The heat treatment process improves the properties of the components, most notably wear resistance and / or toughness.

[0085] The application of this heat treatment yields surprising results. For example, while the hardness of the component may be relatively unaffected, perhaps only slightly reduced (compared to components prepared without heat treatment), wear resistance increases considerably. It has been found that heat treatment converts the W2C+WC structure, one of the two forms of tungsten carbide, to the W+WC structure, which is remarkably different in that it contains metal W and WC. Although not bound by theory, it is thought that the above surprising results may be attributable to the conversion from the W2C+WC structure to the W+WC structure. Heat treatment of tungsten carbide powder is thought to modify the internal structure of the particles, thereby increasing thermal conductivity and / or thermal shock resistance. Standard metal infiltration processes are carried out under conditions of temperature and time that are insufficient to provide the benefits of heat treatment. It has been found that similar wear resistance and toughness benefits can be achieved by increasing the temperature and time beyond conventional infiltration parameters to promote the diffusion of cast tungsten carbide when the metal binder is in the liquid phase.

[0086] In any case, the observation that heat-treated carbide powder yields the above-mentioned unexpected results in components fabricated by the infiltration process indicates that heat-treated carbide powder, as disclosed herein, differs unexpectedly from untreated carbide powder in both structure and properties.

[0087] The heat treatment can be carried out by exposing the powder to a temperature of at least 1000°C to a maximum of 1250°C, preferably at least 1100°C or 1190°C to a maximum of 1250°C, in a non-oxidizing atmosphere for 0.5 to 50 hours, until a partial or complete conversion of the W2C (hemispherical carbide) phase is achieved.

[0088] It is preferable to perform the heat treatment under vacuum (for example, in a vacuum furnace) or in a non-reactive or reducing atmosphere, preferably an oxygen-free atmosphere such as an argon atmosphere, preferably a low-pressure argon atmosphere.

[0089] The manufacturing method also includes a single-step process in which heat treatment is performed simultaneously with the metal infiltration process. In this case, the metal infiltration process is modified, for example, to a higher temperature and / or a longer infiltration time to result in the heat treatment of the tungsten carbide powder. For example, the metal infiltration process can be carried out under heat treatment conditions.

[0090] The infiltration process can use heat-treated carbide as the sole carbide. The use of a blend of heat-treated and unheat-treated carbide is also contemplated. Thus, the present invention includes combinations of blending heat-treated and unheat-treated carbide together to form a porous molded body for the infiltration process. The amount of heat-treated carbide in the carbide powder can be 100% by weight, 90% by weight, 80% by weight, 70% by weight, 60% by weight, 50% by weight, 40% by weight, 30% by weight, 20% by weight, or 10% by weight, based on the total weight of the carbide powder, i.e., the weight of hard particles such as tungsten carbide, e.g., W and all W carbide. A range formed from any two of these values ​​(with or without the endpoints) is also contemplated. For example, when using a blend of heat-treated and unheat-treated carbide, the amount of heat-treated carbide may be in the range of 10-90% by weight, 10-50% by weight, 10-30% by weight, or 70-90% by weight.

[0091] Components made from heat-treated carbide or carbide powder consisting of heat-treated carbide are particularly useful in high-stress applications, such as bearings including thrust bearings and radial bearings.

[0092] Binder alloy: In some embodiments of the present invention, the components include a binder alloy with a high copper content.

[0093] In one embodiment of the present invention, the binder alloy for forming the matrix of the MMC has an elemental composition containing a relatively high copper (Cu) concentration exceeding 55, 60, 65, 70, 75, 80, 85 weight percent (wt%), or a value within the range defined by any one of these values. A higher Cu content improves thermal conductivity, among other advantages. Binder alloys such as those disclosed in International Publication No. 2022 / 212588 (which is incorporated herein in its entirety) can also be used.

[0094] While copper, as an element, can provide one of the highest thermal conductivity, it cannot provide one or more of the other desirable properties related to the manufacture of MMC or the resulting mechanical properties. The inventors have discovered combinations of alloying elements for forming a feedstock alloy for forming the matrix by alloying with Cu in order to improve various mechanical properties of the matrix, including the strength, hardness, and wear resistance of the matrix of the MMC, thereby improving the corresponding mechanical properties of the resulting MMC, as well as the aforementioned penetration properties for forming the matrix in a liquid state. According to various embodiments, in addition to the relatively high Cu content mentioned above, the elemental composition of the feedstock alloy for forming the matrix includes tin (Sn) at a concentration of more than 1.4 wt%, nickel (Ni) at a concentration of more than 3.5 wt%, and manganese (Mn) at a concentration of more than 5.6 wt%. According to embodiments, in order to maintain the high Cu content mentioned above, the total concentrations of Sn, Ni, and Mn do not exceed 20 wt%, 30 wt%, 40 wt%, or 45 wt%, or have values ​​within the range defined by any of these values.

[0095] In some embodiments, the elemental composition of the feedstock alloy for forming the matrix of the MMC contains Sn in concentrations greater than 1.4, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, or 2.6 wt%, or within the range defined by any of these values. For example, the elemental composition contains Sn in concentrations of 1.4–2.6 wt%, 1.7–2.3 wt%, or about 2.0 wt%. The elemental composition of the feedstock alloy further contains Mn in concentrations greater than 5.6, 6.4, 6.8, 7.2, 7.6, 8.0, 8.4, 8.8, 9.2, 9.6, or 10.4 wt%, or within the range defined by any of these values. For example, the elemental composition contains Mn in concentrations of 5.6–10.4 wt%, 6.8–9.2 wt%, or about 8.0 wt%. The elemental composition of the supplied raw material alloy further contains Ni in concentrations exceeding 3.5, 4.0, 4.3, 4.5, 4.7, 5.0, 5.3, 5.5, 5.8, 6.0, or 6.5% by weight, or within the range defined by any of these values. For example, the elemental composition contains Ni in concentrations of 3.5–6.5% by weight, 4.3–5.8% by weight, or approximately 5.0% by weight.

[0096] In some embodiments, the elemental composition of the feedstock alloy may include additional elements, which may include incidental impurities, in total concentrations within the range defined by 10% by weight, 5% by weight, 2% by weight, less than 1% by weight, or any of these values. In some embodiments, Cu may be present as the remainder of the elemental composition, in addition to the additional or impurity elements.

[0097] Advantageously, the relatively high Cu concentration of the feedstock can provide high thermal conductivity and / or electrical conductivity. It will be understood that high thermal conductivity can be measured indirectly by measuring electrical conductivity. According to embodiments, the feedstock has an electrical conductivity greater than a value within the range defined by 2.0 megasiemens (MS) / meter (m), 2.5 MS / m, 3.0 MS / m, 3.5 MS / m, or any of these values. Although not bound by any theory, the feedstock may have a thermal conductivity that can have values ​​related to electrical conductivity, for example, according to the Wiedemann-Franz law. According to embodiments, the feedstock may have a thermal conductivity greater than a value within the range defined by 10 W / mK, 11 W / mK, 12 W / mK, 13 W / mK, 14 W / mK, 15 W / mK, 16 W / mK, or any of these values.

[0098] The combination of high strength and high thermal conductivity of the components further provides high thermal shock resistance. In some embodiments, the thermal shock resistance is 600 W / m or more, in preferred embodiments, the thermal shock resistance is 650 W / m or more, and in more preferred embodiments, the thermal shock resistance is 700 W / m or more.

[0099] When present in the disclosed amounts, combinations of Cu, Sn, Mn, and Ni form feedstock alloys that can offer various advantages over relatively pure elemental Cu as a matrix source for MMCs. These advantages may include one or more of a lower melting temperature, a lower contact angle with tungsten carbide, and / or lower reactivity with tungsten carbide. The combinations of elements may offer further advantages over relatively pure elemental Cu as a matrix source for MMCs, including one or more of higher strength, higher wear resistance, and / or higher hardness.

[0100] In some embodiments, the combination of elements in the feedstock alloy can offer further advantages over the element Cu if the elemental composition of the feedstock does not contain or contains one or more of Si, B, and / or Zn, and if Si, B, and / or Zn are present in combined concentrations within the range defined by 10% by weight, 5% by weight, 2% by weight, less than 1% by weight, or any of these values.

[0101] In more preferred embodiments of the present invention, the Co content of the binder is limited, preferably zero. In some embodiments, the Co content of the binder is less than 1% by weight. In some embodiments, the Co content of the binder is less than 0.1% by weight. In some embodiments, the Co content of the binder is less than 0.01% by weight.

[0102] Having feedstock in alloy form may be advantageous in lowering the melting temperature of the feedstock alloy, and as a result, MMC can be effectively formed at lower temperatures. The lower melting temperature of feedstock in alloy form may be advantageous for several reasons. One reason is compatibility with existing methods for producing MMC, including those described above. Due to the temperature constraints of some existing manufacturing methods, feedstock for forming the matrix of MMC with a melting temperature above 1300K may not melt completely, making it difficult to penetrate the reinforcing particles for production into the matrix of MMC. Therefore, based on the melting temperatures of Cu, Mn, and Ni, which are 1083°C (1356K), 1244°C (1517K), and 1453°C (1726K), respectively, we have found that it is advantageous for feedstock containing these elements to be in alloy form with a melting temperature lower than that of each of these elements. The inventors have found that, advantageously, when a feedstock containing the above-described combination of Cu, Sn, Mn, and Ni elements exists as an alloy, it is possible to advantageously provide a feedstock alloy having a lower melting temperature in order to improve manufacturability. Accordingly, according to embodiments, the feedstock in the form of an alloy has a composition such that the alloy has a solidus temperature lower than the melting temperature of substantially pure Cu. In some embodiments, the solidus temperature of the alloy is lower than a solidus temperature within the range defined by 1300K, 1275K, 1250K, 1225K, 1200K, or any of these values.

[0103] Usage: The compositions and methods described herein can be used to manufacture a wide variety of components. These components may be monoliths entirely manufactured from permeation-cast MMC, or substrate materials bonded to MMC. The permeation process is typically used for drill bit bodies, and these compositions and methods can be used to manufacture drill bit bodies. However, the unique performance regimes of these compositions and methods allow permeation components to be used in an expanded set of application areas.

[0104] Such applications include, but are not limited to, small components such as turning inserts, micro drills, dipper cutters, and other cutters, knives, canning tools, wire dies, blades, water jet nozzles, and wear parts in general.

[0105] Such applications include, but are not limited to, components such as medium-sized parts, including fracking valves, submersible valve assemblies, mining inserts, pump bodies, and thrust bearings.

[0106] Such applications include, but are not limited to, larger components such as bearings, pads for rotary control tools, flow control valves and other valves, chokes, nozzles, and bushings.

[0107] For open-cut mining applications, examples include the following components: slurry pipelines, inserts, valves, choke valves, seats, mud pump components including pump housings or impellers or mud pump components, ore supply chute components including chute blocks, separation screens including but not limited to rotary breaker screens, banana screens, and shaker screens, liners for self-grinding mills and semi-self-grinding mills, ground engagement tools and teeth, shrouds and adapters, wear plates and lock boxes including buckets and dump truck liners, heel blocks for mining shovels, grader blades and surface hardening for grader blades, stacker craters, sizer crushers, jaw crushers, ripper teeth, cutting edges, wear-resistant sleeves and / or wear-resistant surface hardening for general wear packages for mining components and other grinding components.

[0108] Downstream oil and gas applications include the following components, downhole casings and downhole casings, drill pipes and slurry motors, fracking pump sleeves, fracking impellers, fracking blender pumps, stop collars, drill bits and drill bit components, directional drilling equipment and coatings for directional drilling equipment including spiders, pads, stabilizers and centralizers, blowout arresters and coatings for blowout arresters and components including shear rams, oil well tubular goods and coatings for oil well tubular goods, suction rods and couplings, lift plungers, Neyrfor rotors, artificial lift casings, and ESP pump housings and impellers, flow lines and subsea flow lines.

[0109] Upstream applications for oil and gas include process vessels and coatings for process vessels, including steam generators, amine vessels, distillation columns, cyclones, catalytic cracking units, general refining piping, corrosion protection under thermal insulation, sulfur recovery units, convection hoods, sour stripper lines, scrubbers, hydrocarbon drums, and other refining equipment and vessels.

[0110] Applications of pulp and paper include the following components, rolls used in paper machines including Yankee dryers, ventilated dryers, and other dryers, calender rolls, machine rolls, press rolls, winding rolls, digesters, pulp mixers, pulpers, pumps, boilers, shredders, tissue machines, roll and bale handling machines, fiber induction systems, such as deflector blades, doctor blades, evaporators, pulp mills, headboxes, wire components, press components, MG cylinders, pulp reels, winders, vacuum pumps, deflakers, and other pulp and paper equipment.

[0111] For power generation applications, the following components are included: boiler tubes, dust collectors, fireboxes, turbines, generators, cooling towers, condensers, chutes and troughs, augers, baghouses, ducts, ID fans, coal piping, and other power generation components.

[0112] For agricultural applications, the following components are commonly used: chutes, base cutter blades, sugarcane harvesting knives, hammers, troughs, primary fan blades, secondary fan blades, augers, and other components used for mining and other agricultural applications.

[0113] Construction and building applications include structural components such as cement chutes, cement piping, baghouses, mixing equipment, I-beams and concrete substitutes, flooring, kitchen countertops, and other uses.

[0114] Applications for mechanical elements include the following components, shaft journals, hydraulic cylinders, paper rolls, gearboxes, drive rollers, impellers, engine deck reconstruction, propeller shafts and other shafts, general restoration and dimensional restoration applications, and other mechanical element applications.

[0115] Applications for steel include the following components, cold rolling mills, hot rolling mills, wire rod rolling mills, galvanizing lines, continuous pickling lines, continuous casting rolls and other steel rolling rolls, as well as other steel applications.

[0116] Other applications include, for example, vehicle components for use in engines, motors, automatic or manual transmissions, differentials, axles, brakes, and body parts; medical devices, such as implantable devices, device housings, surgical instruments, and surgical tools; and aerospace applications, such as turbines, fans, shafts, nozzles, propellers, fins, and other components for propellers, jets, or rocket equipment, including fins, wings, tail sections, and chassis components.

[0117] Other applications include cold forming tools, drill bits for space mineral exploration, wire dies, inserts for sugar crushers, and crushers for oil sand applications. [Examples]

[0118] Example 1 (Comparative Example): The MMC article was prepared by liquid metal infiltration as follows: A portion of 230 × 450 mesh cast tungsten carbide (CTC) containing spheroidal particles (aspect ratio 1:1) was placed in a mold, and a portion of Cu53 with a nominal composition of 53 wt% Cu, 25 wt% Mn, 15 wt% Ni, and 7 wt% Zn was placed on top of it. This system was heated at 1180°C for 0.25 hours and cooled before testing to produce article 1.

[0119] Item 1 is 675 mm 3 The B611 volume loss and Rockwell hardness of 49 were observed for (0.675cc). The CTC powder showed a Vickers hardness (HV) of 2800-2960.

[0120] As shown in Figures 11a to 11d, the CTC of article 1 exhibited standard cracking and fracturing when subjected to a Palmqvist test using a Vickers indenter (300 gf).

[0121] Example 2: The CTC powder from Example 1 was placed in a vacuum furnace at 1225°C for 20 hours and then cooled. The process was then repeated, but using the heat-treated CTC powder, Article 2 was produced.

[0122] Item 2 is 557 mm 3 The CTC powder exhibited a B611 volume loss of 0.557cc and a Rockwell hardness of 49. The CTC powder showed a Vickers hardness (HV) of approximately 2125.

[0123] As shown in Figures 11e to 11h, the CTC of article 2 showed little to no crushing when subjected to a Vickers indenter (300 gf) (Palmqvist test).

[0124] Examples 3-7: Similar to Example 1, MMC articles in the form of 10 mm square bars were fabricated by liquid metal infiltration using the tungsten carbide shown in Table 1 and the binder alloy shown in Table 2. WC-D is a spherical cast tungsten carbide with a roughened surface. Examples 3-5 are comparative examples. The Charpy impact toughness of the 10 mm square bars was tested according to ASTM E23 without a V-notch.

[0125] [Table 1]

[0126] [Table 2]

[0127] As seen in Figure 11, the absence or reduction of cracks after Vickers indentation indicates that the CTC powder is unexpectedly strengthened by the heat treatment process. As can be seen from the above examples, the use of heat-treated tungsten carbide powder surprisingly increases the toughness of the entire composite.

[0128] Example 8: Coarse, spherical cast tungsten carbide with a particle size of 301 μm was heat-treated in a vacuum furnace at 1225°C for 20 hours. The particles were placed in a mold, and a portion of an alloy with a nominal composition of 85 wt% Cu, 8 wt% Mn, 5 wt% Ni, and 2 wt% Sn was placed on top. Penetration was carried out at 1180°C for 30 minutes. The components were subjected to a high-stress wear test, ASTM B611. A cemented tungsten carbide with 10 wt% cobalt and medium-particle tungsten carbide ranging from 1.4 to 3.4 μm was also tested for comparison.

[0129] As can be seen in Figure 12, 1 cm over a sliding distance of 4902 m. 3The removal of the material was achieved, which is similar to what was observed for the comparative cemented tungsten carbide. All test protocols discussed or suggested herein, such as the ASTM test procedure, are available and known to those skilled in the art.

[0130] While some components, techniques, and embodiments have been described with some degree of detail, it is clear that many modifications can be made to the specific designs, configurations, and methodologies described herein without departing from the spirit and scope of this disclosure.

[0131] Certain features described in this disclosure in the context of separate implementations may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented separately or in any suitable partial combination in multiple implementations. Furthermore, features may be described above as acting in a particular combination, but one or more features from a claimed combination may, in some cases, be removed from the combination, and the combination may be claimed as any partial combination or a variation of any partial combination.

[0132] Furthermore, while methods may be shown in the drawings or described herein in a specific order, such methods do not need to be performed in the specific order shown or in a sequential order, and not all methods need to be performed to achieve the desired result. Other methods not shown or described may be incorporated into the exemplary methods and processes. For example, one or more additional methods may be performed before, after, simultaneously with, or between any of the described methods. Furthermore, methods may be rearranged or rearranged in other implementations. Also, the separation of various system components in the above-described implementations should not be understood as requiring such separation in all implementations, and it should be understood that the described components and systems can generally be integrated together in a single product or packaged in multiple products. Furthermore, other implementations are also within the scope of this disclosure.

[0133] Conditional language such as "can," "could," "might," or "may," unless otherwise specified or understood in the context in which they are used, is generally intended to convey whether a particular embodiment includes or does not include a particular feature, element, and / or process. Therefore, such conditional language is generally not intended to imply that the feature, element, and / or process is required in any way for one or more embodiments.

[0134] Connective language, such as the phrase "at least one of X, Y, and Z," is generally understood separately in the context in which it is used to convey that an item, term, etc., may be one of X, Y, or Z, unless otherwise specified. Therefore, such connective language is not generally intended to mean that a particular embodiment requires the presence of at least one of X, at least one of Y, and at least one of Z.

[0135] As used herein, the terms “approximately,” “about,” “roughly,” and “substantially” refer to values, quantities, or characteristics close to the stated value, quantity, or characteristic that still perform the desired function or achieve the desired result. For example, the terms “approximately,” “about,” “roughly,” and “substantially” may refer to quantities within a range of 10% or less, 5% or less, 1% or less, 0.1% or less, and 0.01% or less of the stated quantity. If the stated quantity is 0 (e.g., none, not), the above ranges may be specific ranges, but not within a specific percentage of that value. For example, within a range of 10% or less by weight / volume of the stated quantity, within a range of 5% or less by weight / volume, within a range of 1% or less by weight / volume, within a range of 0.1% or less by weight / volume, and within a range of 0.01% or less by weight / volume.

[0136] Several embodiments have been described in reference to the accompanying drawings. While the drawings are drawn to scale, such scale should not be limiting, and dimensions and proportions other than those shown are intended and within the scope of the disclosed invention. Distances, angles, etc., are for illustrative purposes only and do not necessarily have a precise relationship to the actual dimensions and layout of the illustrated devices. Components may be added, removed, and / or rearranged. Furthermore, any particular features, aspects, methods, characteristics, features, qualities, attributes, elements, etc., disclosed herein in relation to various embodiments may be used in all other embodiments described herein. Furthermore, it will be recognized that any method described herein may be carried out using any device suitable for performing the described process.

[0137] While several embodiments and their variations have been described in detail, other modifications and their uses will be obvious to those skilled in the art. Therefore, it should be understood that various applications, modifications, materials, and substitutions can be fabricated from equivalents without departing from the unique and inventive disclosure or claims of this specification.

Claims

1. Tungsten carbide powder containing granules having a particle interface integral ratio of 20% to 50% and an average aspect ratio of less than 1.

3.

2. A heat-treated tungsten carbide powder prepared by heating the tungsten carbide powder described in claim 1 at a temperature of 1000 to 1250°C for 0.5 to 50 hours under vacuum, a non-reactive atmosphere, or a reducing atmosphere.

3. The heat-treated tungsten carbide powder according to claim 2, wherein the heat-treated tungsten carbide contains a tungsten carbide (monocarbide) phase, a metallic tungsten phase, and optionally a hemispherical carbide (W2C) phase, and the tungsten phase contains 1 to 50% by weight of the heat-treated tungsten carbide powder.

4. The heat-treated tungsten carbide powder according to claim 1, having a carbon content of 3.0 to 4.5% by weight.

5. A composition comprising the tungsten carbide powder described in claim 1 and an alloy containing 50 to 85% by weight of copper, wherein a metal matrix composite is formed.

6. The composition according to claim 5, wherein the alloy further comprises 1.4 to 2.6% by weight of Sn, 5.6 to 10.4% by weight of Mn, and 3.5 to 6.5% by weight of Ni.

7. A method for manufacturing a metal matrix composite article, To obtain tungsten carbide powder containing heat-treated tungsten carbide powder, In the presence of a binder alloy, the tungsten carbide powder is heated to a temperature and for a time sufficient to cause the binder alloy to melt and penetrate the tungsten carbide powder, thereby forming a permeated article. The metal matrix composite article is obtained by cooling the permeating article to solidify the binder alloy, Includes, The method wherein the binder alloy contains 50 to 85% by weight of copper.

8. The method according to claim 7, wherein the heat-treated tungsten carbide powder comprises granules having a particle interface integral ratio of 20% to 50% and an average aspect ratio of less than 1.

3.

9. The method according to claim 7, wherein the heat-treated tungsten carbide powder has a carbon content of 3.0 to 4.5% by weight.

10. The heat-treated tungsten carbide powder contains 1 to 50% by weight of tungsten phase and hemispherical carbides (W ２ C) The method according to claim 7, which may or may not contain phase C.

11. A metal matrix composite article prepared by the method described in claim 7.

12. A metal matrix composite article containing tungsten carbide particles in an alloy matrix, The tungsten carbide particles have a particle interface integral ratio of 20% to 50% and an aspect ratio of 1 to 1.3, and based on the total weight of the tungsten carbide particles, they comprise 10% to 100% by weight of heat-treated tungsten carbide particles. The alloy matrix is ​​a metal matrix composite article containing 50 to 85% by weight of copper.

13. When measured according to ASTM G65, 6 mm ３ The metal matrix composite article according to claim 12, exhibiting the following wear resistance.

14. The metal matrix composite article according to claim 12, which exhibits a volume loss of 0.8 cc or less when measured according to ASTM B611.

15. The metal matrix composite article according to claim 12, exhibiting a Charpy impact toughness of at least 6.8 J.

16. The metal matrix composite article according to claim 12, wherein the tungsten carbide particles have a D50 of 1 μm to 10 μm and a TRS of 360 ksi or more.

17. The metal matrix composite article according to claim 12, wherein the tungsten carbide particles have a D50 of 11 μm to 20 μm and a TRS of 280 ksi or more.

18. The metal matrix composite article according to claim 12, wherein the tungsten carbide particles have a D50 of 21 μm to 40 μm and a TRS of 230 ksi or more.

19. The metal matrix composite article according to claim 12, wherein the tungsten carbide particles have a D50 of 41 μm to 60 μm and a TRS of 180 ksi or more.

20. The metal matrix composite article according to claim 12, wherein the tungsten carbide particles have a D50 of 61 μm to 80 μm and a TRS of 160 ksi or more.

21. The metal matrix composite article according to claim 12, wherein the tungsten carbide particles have a D50 of 81 μm to 100 μm and a TRS of 140 ksi or more.

22. The metal matrix composite article according to claim 12, wherein the tungsten carbide particles have a D50 of 111 μm to 200 μm and a TRS of 100 ksi or more.

23. The metal matrix composite article according to claim 12, wherein the tungsten carbide particles have a D50 of 201 μm to 500 μm and a TRS of 80 ksi or more.

24. The metal matrix composite article according to claim 12, wherein the tungsten carbide particles have a D50 of 501 μm to 1000 μm and a TRS of 60 ksi or more.

25. The metal matrix composite article according to claim 12, wherein the tungsten carbide particles have a D50 of 1001 μm to 2000 μm and a TRS of 50 ksi or more.

26. The metal matrix composite article according to claim 12, wherein the tungsten carbide particles comprise 10% to 100% by weight of heat-treated tungsten carbide particles based on the total weight of the tungsten carbide particles.

27. The heat-treated tungsten carbide particles according to claim 26, which are heated to a temperature of 1000 to 1250°C for 0.5 to 50 hours under vacuum or in a non-reactive atmosphere prior to the liquid metal infiltration process.

28. The heat-treated tungsten carbide particles according to claim 26, wherein during the liquid metal infiltration process, the particles are heated in the presence of a liquid metal at a temperature of 1000 to 1250°C, preferably 1190 to 1250°C, for 0.5 to 50 hours.

29. The heat-treated tungsten carbide particles according to claim 26, having a carbon content of 3.0 to 4.5% by weight.

30. It contains 1 to 50% by weight of tungsten phase, and optionally includes hemispherical carbide (W ２ C) Heat-treated tungsten carbide particles according to claim 26, comprising phase C.

31. The metal matrix composite article according to claim 12, wherein the alloy matrix further comprises 1.4 to 2.6 wt% Sn, 5.6 to 10.4 wt% Mn, and 3.5 to 6.5 wt% Ni.

32. The metal matrix composite article according to claim 12, wherein the composite comprises a first region in which the metal matrix composite is a high-strength matrix metal composite material and a second region in which the metal matrix composite is a high-wear-resistant matrix metal composite material.

33. The metal matrix composite article according to claim 12, wherein the matrix metal composite article comprises a plurality of regions, each region comprising 10% to 100% by weight of the heat-treated tungsten carbide particles based on the total weight of the tungsten carbide particles in the respective region.

34. Obtaining the above involves heating tungsten carbide powder containing granules having a particle interface integral ratio of 20% to 50% and an average aspect ratio of less than 1.3 at a temperature of 1000°C to 1250°C for 0.5 to 50 hours under vacuum, a non-reactive atmosphere, or a reducing atmosphere to obtain tungsten carbide powder containing at least 10% by weight of heat-treated tungsten carbide powder based on the total weight of the tungsten carbide powder, or The method according to claim 7, wherein obtaining the foregoing comprises heating tungsten carbide powder having a grain interface integral ratio of 20% to 50% and an average aspect ratio of less than 1.3 in the presence of a molten binder alloy at a temperature of 1000 to 1250°C for 0.5 to 50 hours, wherein 100% by weight of the tungsten carbide powder in the impregnated article is heat-treated tungsten carbide powder.

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